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closed loop tuning

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Old Dec 31, 2011 | 09:55 AM
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Default closed loop tuning

I'm pretty new to tuning, using efilive to tune my 99 camaro. I believe my VE and Maf tables are pretty good so far. WO2BEN is pretty much 1.0 across the board. Before it hits closed loop it is at 1.0, but once its in closed loop the WO2BEN drops to .97-.98 and LTFTBEN goes up to 1.02-1.04 on average. This seems to me to indicate the nb O2 sensors are either bad or need help finding stoich.

I have tried playing with O2 switch points and stft delay but it results seem to be pretty random. Car has kooks longtubes, careless true duals and O2 extenders. Should my first stop be replacing the o2s? I tried my front and rear sensors in the front position since I am only running front sensors. And the wideband is about 2" away from the drivers side nb O2.
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Old Dec 31, 2011 | 10:16 AM
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conditions are always going to change, I would not be worrying about 2% of error. That is better than most stock calibrations on stock cars. You can fight it all day long, it will be different another day/ different gas tank/ different system voltage, ect...

Are you having drivability issues from this? At wide open throttle are you getting what you want for ratios?

I would not be to worried.
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Old Dec 31, 2011 | 11:38 AM
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no driveability issues so far. Everything seems to be ok. I just thought I was strange that the wideband would say everything is good and then at the same time in closed loop the ltfts are all wacky. 1.02 is average but it bounces alot, I've seen 8-10% at times but not sustained for more than a minute or two. And it seems that closed loop mode 8 and 64 are usually close to 0% but everything in between averages to 3-5% throughout the log.
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Old Dec 31, 2011 | 12:02 PM
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Did you do the tune in SD first, then re introduce the maf? IF not, that is probably the problem. You are blending during transistions of throttle causing skewing one way or another maybe?
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Old Dec 31, 2011 | 01:23 PM
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I did everything in sd first. Then added the maf. Then did timing. Then doublechecked ve, then maf (just to make sure there were no major changes, which there werent), then enabled closed loop.
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Old Dec 31, 2011 | 01:26 PM
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It could be a lot of little things effecting it. Just make the trims close to 0 and move on to the next thing. It is always going to change. that is what it is there for. If it is skewing wrong like you think, then it could be an exhaust leak or vacume leak or the headers arent getting the o2 sensors hot enough? Or to hot.
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Old Dec 31, 2011 | 02:21 PM
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you're probably right. I'll give it a few days. I just figured that if the o2s were working right my wo2ben would still be 1.0 regardless of ltft
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